The employees testified yesterday and explained how crucial Sars units were disbanded and the revenue collector lost the ability to measure compliance.

The new operating model was introduced by now suspended Sars commissioner Tom Moyane when he was appointed in 2014.

President Cyril Ramaphosa appointed retired judge Robert Nugent in June to chair the commission to probe allegations of financial misconduct at Sars, including a shortfall of R50 billion between 2014 and 2018 while it was under Moyane.

Ramaphosa suspended Moyane following a breakdown of trust in his running of the organisation. The hearings are expected to run until next week Friday.